614 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii. 



tPTYCHOBRANCHUS TRINACRUS Lea. 



"Unio trinacrns Lea, Pr. Ac. N. Sci., Phila., V, 1861, p. 59; "^ Jl. Ac. N. Sci., Phila., 

 V, 1862, p. 86, pi. XII, fig. 235; *Obs., VIII, 1862, p. 90, pi. xii, fig. 235.— 

 *SowERBY, Conch. Icon., XVI, pi. lxxxi, fig. 428.— *B. H.Wright, Check 

 List, 1888. 



*ikfa»'5farow ( ZTwio) <nnao»'MS Lea, Syn., 1870, p. 36. 



Ooosa Eiver, Alabama. 



tPTYCHOBRANCHUS GREENI Conrad. 



* Uniogreeni Conrad, New F. W. Shells, 1834, p. 32, pi. iv, fig. 1, p. 69.— *Ferussac, 



Guer. Mag., 1835, p. 29.—* Moller, Syn. Nov. Gen., 1836, p. 203.—* Conrad, 

 Monog.,VIII, 1837, p. 69, pi. xxxviii, fig. 2.— *HANLEY,Test. Moll. ,1842, p. 191; 

 * Biv. Shells, 1843, p. 191, pi. xxiv, fig. 6.—* Chenu, Bib. Conch., Istser., 1845, 

 p. 17, pi. Ill, fig. 5. — *Catlow and REEVE,Conch. Nom., 1845, p. 59. — *Conrad, 

 Pr. Ac. N. Sci. Phila., VI, 1853, p. 250,—* H. and A. Adams, Gen. Rec. Moll., II, 

 1857, p. 494.—* Sowerby, Conch. Icon., XVI, 1866, pi. xlvii, fig. 253.—* B. H. 

 Wright, Check List, 1888.—* P^tel, Conch. Sam., Ill, 1890, p. 154. 



* Margarita ( Unio) greeni Lea, Syn., 1836, p. 24; 1838, p. 19. 



* Margaron ( Unio) greeni Lea, Syn., 1852, p. 27; 1870, p. 42. 



t* Unio simplex Lea, Pr. Am. Phil. Soc, IV, 1845, p. 163; *Tr.Am. Phil. Soc, X, 

 1848, p. 76, pi. V, fig. 15 ; * Obs., IV, 1848, p. 50, pl.v, fig. 15.—* H. and A. Adams, 

 Gen. Rec. Moll., II, 1857, p. 494.—* B. H. Wright, Check List, 1888.— *PiETEL 

 Conch. Sam., Ill, 1890, p. 167. 



* Margaron ( Unio) simplex Lea, Syn., 1852, p. 27 ; 1870, p. 42. 



Black Warrior River, Alabama. 



tPTYCHOBRANCHUS FLAVESCENS Lea. 



* Unio flavescens Lea, i Pr. Am. Phil. Soc, IV, 184.5, p. 163; Tr. Am. Phil. Soc, X, 



1848, p. 72, pi. HI, fig. 9; * Obs., IV, 1848, p. 46, pi. in, fig. 9.—* Conrad, Pr. 

 Ac. N.Sci. Phila., VI, 1853, p. 249.— * H. and A.Adams, Gen. Rec. Moll., II, 

 1857, p. 494.—* B. H. Wright, Check List, 1888. 



* Margaron ( Unio) flavescens Lea, Syn., 1852, p. 27; 1870, p. 43. 



* Unio flavescens P^tel, Conch. Sam., III. 



Black Warrior Eiver, Alabama. 



ESCHATIGEN^^. 



Male and female shells alike; embryos iu distinct, short ovisacs, 

 forming a border to the entire outer gills. 



Genus DROMUS Simpson, 1900. 

 (Type, Unio dromus hea.) 



Shell solid, rounded-triangular; beaks well forward, rather high; beak 

 sculpture consisting of line ridges running parallel with the growth 

 lines, the furrows between the ridges interrupted at the posterior ridge; 

 posterior ridge distinct; a series of humps runs from the beaks down to 

 the central part of the base of the shell, which is otherwise sculptured by 



' I have only seen a single shell of this, and it is not in the best condition. It may 

 be only a form of greeni, but it is not so inflated or solid, and it has no rays. 



